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1.18. CHAPTER 1, PROBLEM 18
19
1.18
Chapter 1, Problem 18
Problem:
How long would it take to count the molecules in a cubic micron of water
(1 micron is
10
−
4
cm) with a very fast electronic counter that can count at a rate of
three million molecules per second?
Solution:
One micron is 10
−
4
cm, which is also 10
−
3
mm. We know from the text that
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Unformatted text preview: 1 mm 3 of water at STP contains 3 . 34 · 10 19 molecules. Hence, 1 cubic micron of water contains 3 . 34 · 10 10 molecules. The time to count them at a rate of three million per second is t = 3 . 34 · 10 10 molecules 3 · 10 6 molecules / sec = 11133 seconds = 3 . 09 hours...
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This note was uploaded on 02/09/2012 for the course AME 309 taught by Professor Phares during the Spring '06 term at USC.
 Spring '06
 Phares

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